Electronic devices containing active organic materials are attracting increasing attention for use in devices such as organic light emitting diodes (OLEDs), organic photoresponsive devices (in particular organic photovoltaic devices and organic photosensors), organic transistors and memory array devices. Devices containing active organic materials offer benefits such as low weight, low power consumption and flexibility. Moreover, use of soluble organic materials allows use of solution processing in device manufacture, for example inkjet printing or spin-coating.
An OLED may comprise a substrate carrying an anode, a cathode and one or more organic light-emitting layers between the anode and cathode.
Holes are injected into the device through the anode and electrons are injected through the cathode during operation of the device. Holes in the highest occupied molecular orbital (HOMO) and electrons in the lowest unoccupied molecular orbital (LUMO) of a light-emitting material combine to form an exciton that releases its energy as light.
A light emitting layer may comprise a semiconducting host material and a light-emitting dopant wherein energy is transferred from the host material to the light-emitting dopant. For example, J. Appl. Phys. 65, 3610, 1989 discloses a host material doped with a fluorescent light-emitting dopant (that is, a light-emitting material in which light is emitted via decay of a singlet exciton).
Phosphorescent dopants are also known (that is, a light-emitting dopant in which light is emitted via decay of a triplet exciton).
A hole-transporting layer may be provided between the anode and light-emitting layer of an OLED.
Suitable light-emitting materials include small molecule, polymeric and dendrimeric materials. Suitable light-emitting polymers include poly(arylene vinylenes) such as poly(p-phenylene vinylenes) and polymers containing arylene repeat units, such as fluorene repeat units. Blue light-emitting fluorene homopolymer is disclosed in WO 97/05184.
WO 00/53656 discloses a method of forming a conjugated polymer by reacting a monomer carrying halide reactive functional groups and a monomer carrying boron derivative reactive functional groups in the presence of a palladium catalyst.
WO 2005/013386 discloses an organic light-emitting device comprising a host polymer material and a luminescent metal complex wherein the polymer material may comprise non-planar repeat units or partially or fully non-conjugated repeat units in order to reduce conjugation of the polymer.
WO 2011/141709 discloses a light-emitting composition comprising a host polymer and a light-emitting dopant wherein the host polymer comprises conjugating repeat units and non-conjugating repeat units in a backbone of the polymer. The non-conjugating repeat units comprise an at least partially saturated ring having at least one ring atom that breaks any conjugation path between repeat units linked to the non-conjugating repeat units.
WO 2010/085676 discloses host materials for electrophosphorescent devices. A copolymer formed by copolymerization of 1,6-bis(3-(4,4,5,5-tetramethyl-[1,3,2]-dioxaborolan-2-yl)phenoxyl)hexane and 2-(4-(3-(3,6-dibromocarbazol-9-yl)propyl)phenyl)-4,6-di(3-methylphenyl)-1,3,5-triazine is disclosed.
JP 2005/158561 discloses non-conjugated polymers containing an electron transporting compound.
US 2011/095269 discloses the following polymer:

WO 2012/048778 discloses polymers formed by polymerization of the following monomers:

U.S. Pat. No. 7,898,163 discloses a monomer having the following formula:
